Create ubint_test.py
Create ubint_test.py

TODO: the numerical stability of function \exp(-\beta(a_1 x_1 + a_2 x_2^2 + a_3 x_3^3 +...)) is poor. If the highest order of a_i obtained from the samples is negative, the normalization factor infinity. Try to find better ways to estimate a_i from samples.
Shirui816/UmbrellaIntegrate.py